Piston ring



Patented Mar. 3, 1925.

UNITED STATES LOUIS FRANKLIN DAVIS, 01? ATLANTA, GEORGIA.

PISTON RING.

Application filed November 17, 1923. Serial No. 75,349.

To all whom it may concern:

Be it known that 1, Louis F. DAvIs, a citizen of the United States, residing at Atlanta, in the county of Fulton and State of Georgia, have invented a new and useful Piston Ring, of which the following is a specification. v

This invention relates to piston rings, and its principal object is to construct'a ring having special means to prevent leakage of the oil into the firing chamber, or leakage of the fuel into the crank case, said means being in effect a double acting valve attached to the ring.

The structure by means of which this desired result is obtained, and the principles of the operation will be more fully described in connection with the accompanying drawing, which illustrates the preferred form of the invention.

In the drawing:

Figure 1 is a perspective View of one of the piston rings detached and expanded.

Figure2 is a sectional view through a cylinder having a piston with rings constructed according to my invention.

Figure 3 is a side elevation showing the meeting ends of the ring separated.

Figure 4 is a similar view, but with the outer or main portion of the ring broken away.

Figure 5 is a sectional view taken through the ring, and showing the valved joint in elevation.

Figure 6 is a transverse section through the cylinder adjacent one of the rings, and showing the latter in normal position.

Figure 7 is :a similar view showing the position of the valves during the power stroke, and also during the compression stroke.

In the drawing, the invention is shown in connection with a cylinder 10, in which operates a piston 11, having the usual grooves 12 for receiving the piston rings. The ring which embodies my invention includes an outer resilient body portion 13, of suitable shape and size to yieldingly engage the inner wall of the cylinder 10. Rectangular recesses 14 and 15 are cut in the ends of the ring portion 13 in offset relation, so as to leave tongues 16 and 1.7, which are adapted to overlap each other when the ring is pressed into the cylinder. An inner ring 18, in the shape of a thin leaf spring, is intermediately secured by welding or other suitable means, asshown at 19, to theinner side of the ring portion 13 at'a point diametr cally oppbsit t th ov rl pping end 16 nd 1 The end o he eaf sp ng have rectangular notches 2 0 and 21 cut therein leaving tongues 22 and 23,- whichextend over the recesses 14 and 15, normally closing the same.

The tongues 22 and 23 normally close the recesses 14 and 15 between the ends of the ring portion 13, and form in effect check valves, which are easily yieldable in response to pressure from the outside, by reason of the fact that the ring 18 is attached to the ring portion 13 only at the point 19. Pressure from the inside of the ring, however, tightly closes the valves.

In analyzing the valve, action of the invention, it should be noted that during the compression stroke, as will be seen from a consideration of Figures 1 and 2, the pressure from the firing chamber, which reaches the upper piston ring, will enter through the recess 15 and open the upper valve or tongue 22 at one end of the spring member 18. The pressure thus admitted into the groove 12'inside the ring will exert an outward pressure against the tongue or valve 23. Thus, as the pressure in the firing chamber increases, the outward pressure against the tongue 23 increases, and prevents any gaseous vapor from getting past the ring in the direction of the crank case. The position of the spring member 18 during the compression stroke is shown in Figure 7 somewhat exaggerated.

During the intake stroke, the suction from the cylinder added to the atmospheric pressure from the crank case reverses the action of the valves, closes tightly the upper valve or tongue 22, preventing any oil from passing the ring, exerts pressure on the inner surface of the ring and forces it hard against the cylinder wall.

Heretofore, it has been impossible after the piston and cylinder became somewhat worn to prevent leakage of the oil into the firing chamber, or to prevent leakage of the gaseous vapor into the crank case. This leakage lowers the efficiency of the engine, impairs the lubricating quality of the oil and also causes loss of compression. By means of the present invention, pressure is exerted on the inside of the ring, during both the intake and compression strokes, so that this leakage is prevented, and the ring is made to fit the cylinder even though the latter is Worn out of round. The use of the valve joint also makes it possible to dispense with the use of the high spring tension on the cylinder Walls permitting thinner rings, saving Wear and absorption of power. The successful operation of the invention is not materially aiiected by the Wearing away of the rings and piston. It may be said, therefore, that the life of the ring is limited only When it is Worn thin enough to break, because the Wear can never prevent the lapping of the valve pieces.

While I have shown and described specifically the construction of the invention, it is to be understood that this is merely illustrative and that minor variations may be made in the relative size, shape and arrangement of the several parts, Without departing from the salient principles of the invention as claimed. It will also be understood that, although I have described the invention as especially adapted for use in an internal combustion engine, it may also be used to advantage in pumps or steam engines.

lVhat is claimed is: y

l. A piston ring comprising a body por tion having its ends recessed to form laterally. lapped tongues, and means secured to the inside of the body portion at a distance from its ends and yieldably covering said recesses.

2. A piston ring comprising a body portion having its ends recessed to form laterally lapped tongues, and means secured to the inside of the body portion and normally covering said recesses, said means being yieldable in response to pressure or suction on the piston to selectively uncover the respective recesses.

3. A piston ring comprising a body portion having its ends recessed to form laterally lapped tongues, and relatively thin leaf, spring portions yieldably covering the respective recesses and forming check valves therefor. v

4. A piston ring comprising a body portion having its ends recessed to form laterally lapped tongues, and a relative thin inner ring having its intermediate portion secured to the body portion diametrically opposite to said ends, said inner ring having ends which normally cover the recesses in the body portion and act as check valves.

5. A piston ring comprising a body portion having rectangular recesses cut in the tWo ends thereof in offset relation, so as to provide tongues Which overlap each other, and an inner ring in the form of a leaf spring'oit substantially the same width'and length as the body portion, said inner ring being rigidly secured to the body portion and having its ends provided with rectangular notches defining tongues which extend over the recesses and normally cover the same, and form check valves therefor.

In testimony that I claim the foregoing as my own, I have hereto affixed my sig nature.

LOUIS FRANKLIN DAVIS. 

